Winding core



FIG. 1 is a perspective view of the winding core;

FIG. 2 is a front view thereof;

FIG. 3 is a plan view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a sectional view thereof taken at 5-5 of FIG. 3; and,

FIG. 6 is a perspective view shown in an environment of use.

The portions shown in broken lines do not form part of the claimed design. 

CLAIM The ornamental design for a winding core, as shown and described. 